Snow-streaked cones at the summit of dormant Mauna Kea volcano serve as a foreground for monstrous Mauna Loa, which rises 56,000 feet (17,000 meters) from the ocean floor to its gradual peak. Called a shield volcano for the gently sloping mounds its fluid lava produces, Mauna Loa is one of two active volcanoes in Hawai'i Volcanoes National Park, and one of five in the state of Hawai'i. Scientists say she's overdue to erupt: Her last blast occurred in 1984.